Design and demonstration of an automated cell-based biosensor

Cell-based biosensors have the capacity to respond to a wide range of analy tes in a physiologically relevant manner and appear well-suited for toxicit y monitoring of both known and unknown analytes. One means of acquiring cel lular functional information for biosensor applications involves extracellu lar recording from excitable cells, which can generate noninvasive and long -term measurements. Previous work from our laboratory described a prototype portable system capable of high signal-to-noise extracellular recordings, in spite of deficiencies in thermal control, fluidics handling. and absence of data acquisition (DAQ) capability. The present work describes a cell-ba sed biosensor system that incorporates low noise amplifier and filter board s, a two-stage thermal control system with integrated fluidics and a flexib le graphical user interface for DAQ and control implemented on a personal c omputer. Wherever possible, commercial off-the-shelf components have been u tilized for system design and fabrication. The system exhibits input-referr ed noise levels of 5-10 muV(RMS), such that extracellular potentials exceed ing 50-60 muV can be readily resolved. In addition, the biosensor system is capable of automated temperature and fluidics control. Flow rates can rang e from 0-2.5 ml/min, while the cell recording chamber temperature is mainta ined within a range of 36-37 degreesC. To demonstrate the capability of thi s system to resolve small extracellular potentials, recordings from embryon ic chick cardiac myocytes have been performed. (C) 2001 Elsevier Science B. V. All rights reserved.